In this work, we describe the "in situ" synthesis of "all-acrylic" copolymer (n-butyl acrylate-co-methyl methacrylate)/clay materials at different low contents of raw and modified Montmorillonite (1-4 wt % versus monomer). The cationic 2,2' azobis-(amidinopropane)dihydrochloride initiator was used to modified the clay by cation exchange in combination with the N-tert-butyl-N-[1-diethylphosphono-(2,2-dimethylpropyl)] (SG1) nitroxide to synthesize the polymer/clay nanocomposite via nitroxide mediated controlled radical polymerization. All synthesized materials are characterized by proton nuclear magnetic resonance, size exclusion chromatography, thermogravimetric analysis and differential scanning calorimetry techniques. The thermo-mechanical properties of the synthesized materials are also reported. The results show that a decrease in molar masses and/or slight changes in molar compositions of poly (n-butyl acrylate- co-methyl methacrylate)/clay systems can be balanced by clay loading in polymer matrix, and consequently compensated or masked clay effects on physical properties of obtained materials. © 2012 Wiley Periodicals, Inc.